Didn't stop fleas after Lotilaner (Credelio) in dogs

The FDA has received 613 reports of didn't stop fleas in dogs after Lotilaner. That is 6.2% of all reports for this medicine, compared with 6.2% across reports for all dog medicines.

613Reports

1.3%Marked serious

0.2%Recovered

0.5%Died or euthanised

16 daysTypical onset

How soon it started

Same day

62 13%

1–2 days

42 8.5%

3–7 days

61 12%

1–4 weeks

148 30%

Over a month

183 37%

How the animals did

Recovered

1 0.2%

Still unwell when reported

72 12%

Died

2 0.3%

Euthanised

1 0.2%

Not known

537 88%

Problems reported at the same time

79 13%

22 3.6%

15 2.4%

13 2.1%

13 2.1%

12 2.0%

11 1.8%

10 1.6%

Age of the animals

Under 1 year

1–3 years

125

4–7 years

146

8–11 years

100

12+ years

About this medicine

Lotilaner kills fleas and ticks; monthly chewable.

Products with this ingredient include Credelio. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

In 2018 the FDA alerted owners and vets that isoxazoline products have been associated with neurologic reactions such as muscle tremors, wobbliness (ataxia) and seizures, including in animals with no history of them.

Questions owners ask

Can Lotilaner cause didn't stop fleas in dogs?: 613 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 16 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Didn't stop fleas with similar medicines

Didn't stop fleas after Fluralaner (Bravecto) 16,499 reports · 24% of its reports
Didn't stop fleas after Afoxolaner (NexGard) 5,900 reports · 10% of its reports
Didn't stop fleas after Sarolaner (Simparica) 1,139 reports · 6.8% of its reports
Didn't stop fleas after Afoxolaner + Moxidectin + Pyrantel (NexGard PLUS) 372 reports · 4.0% of its reports
Didn't stop fleas after Lotilaner + Moxidectin + Praziquantel + Pyrantel (Credelio Quattro) 84 reports · 2.7% of its reports

All reported side effects of Lotilaner in dogs · Medicines most reported with didn't stop fleas